Reeling self-adhesive labels

ABSTRACT

To produce a continuous reel of self-adhesive labels without the limitations on size and quality involved in printing on a continuous web, the labels are initially produced as separate flat sheets, cut to finished size and stacked, and are then fed in succession from the stack to an adhesive applicator, through an adhesive drying device, and applied successively by their adhesive coated sides to a continuous web of release paper which is then reeled. The labels may be fed from the stack to the surface of a drum, by a reciprocating suction bar, and held by suction on the surface of the drum while the adhesive is applied and dried. The web of release paper is then brought into contact with the labels at the point at which the suction ceases to hold them on the drum.

Unite @tates tet instance Mar.- 4, 1975 REELING SELF-ADHESIVE LABELS [75] lnventorz David John Instance, West Malling, England [73] Assignee: David J- llnstance Limited, Tombridge, Kent, England [22] Filed: Mar. 15, 1973 [21] Appl. No.: 341,636

30 Foreign ApplicationPriority Data Mar. 16, 1972 Great Britain 12384/72 [52] US. Cl 156/285, 156/289, 156/302, 156/499, 156/519, 156/552, 27D/58 [51] Int. Cl....., .L B29c 17/00 [58] Field of Search 156/382, 497, 499, 552, 156/566, 578, 555, 560,562, 567, 568, 571,

58; 93/8 WA, 61 A, 63 R, 63 M; 161/38, 406

[56] References Cited UNITED STATES PATENTS 2,527,272 10/1950 Lyon et a1 156/519 2,613,007 10/1952 Hofe 216/55 2,743,753 5/1956 Graveset al 156/519 Primary Examiner Charles E. Van Horn Assistant Examiner-Neal Kalishtnan Attorney, Agent, or Firm-Sughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT To produce a continuous reel oil self-adhesive labels without thev limitations on size and quality involved in printing on a continuous web, the labels are initially produced as separate flat sheets, cut to finished size 'and stacked, and are then fed in succession from the l stack to an adhesive applicator, through an adhesive drying device, and applied successively by their adhesive coated sides to a continuous web of release paper which is then reeled. The labels may be fed from the stack to the surface of a drum, by a reciprocating suction'bar, and held by suction on the surface of the drum while the adhesive is applied and dried.

The web of release paper is then brought into contact with the labels at the point at which the suction ceases to hold them on the drum.

11 (Ilaims, 2 Drawing Figures BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to the reeling of self-adhesive labels.

2. Description of the Prior Art Because of the increasing mechanization of packaging equipment, there is an increasing demand for selfadhesive labels (i.e., labels coated on the reverse side with a pressure-sensitive adhesive) to be supplied to product manufacturers or packers in a continuous web in reeled form. The web must of course have a backing of release paper to prevent adjacent turns of the reel from sticking together. The web can then be unreeled and fed into the packaging equipment, which peels the labels from the web of release paper and applies the individual labels by pressure.

The printing methods which can be used to print labels on to a continuous web, which can be subsequently coated with a release paper backing and reeled, are those known as gravure, letterpress and flexography, all of which have severe limitations in terms of quality and the size of the label which can be printed, except for gravure, which is good only for long machine runs as the cost of preparation is high. For example, using letterpress it is not at present possible to print labels larger than about X 6 inches on the continuous web. If the labels are printed on flat sheets the size limitations become less acute and other printing methods, such as offset lithography, screening or bronzing, can be employed which enable better quality labels to be produced at high speed.

SUMMARY OF THE INVENTION The present invention aims to avoid the limitations on size and quality previously associated with printing labels on to a continuous web, while retaining the convenience which comes from having the labels on a reel.

According to the present invention, I provide a process for the production of a continuous reel of selfadhesive labels, wherein the labels are produced as separate flat sheets cut to finished size and stacked, the separate labels are then fed in succession from the stack to an applicator by which they are coated individually on their reverse sides with a pressure-sensitive adhesive composition, and the labels are applied successively by their adhesive-coated sides, to a continuous web of release paper which is then reeled.

After being coated with the adhesive composition the labels may be fed through a heating device which dries the adhesive, before being applied to the web of release,

paper. The adhesive may be dried by hot air while the labels are held by suction on the surface of a rotating drum.

The application of the labels to the web of release paper may be controlled by a photo-electric cell sensitive to the presence of a preceding label on the web.

The invention also resides in apparatus for producing continuous reels of self-adhesive labels, comprising means for supporting a stack of labels in the form of separate flat sheets cut to finished size, means for feecling separate out labels in succession from the stack to an applicator which is arranged to coat the reverse sides of the labels individually with a pressuresensitive adhesive composition, means for subsequently applying the labels successively by their adhesive-coated sides to a continuous web of release paper and means for reeling the continuous web.

The applicator may comprise a roller, a doctor blade, or means for spraying or screening the adhesive on to the labels.

The means for feeding the cut labels from the stack to the applicator may comprise a reciprocatable suction bar.

The apparatus preferably further comprises means for drying the adhesive composition, and means for feeding the coated labels from the applicator to the drying means and thence to the means for applying the labels to the continuous web. The drying means may comprise an enclosure and means for supplying hot air to the enclosure; The means for feeding labels from the applicator may comprise a rotatable drum with means for holding the labels thereon by suction. The drum may have a perforated cylindrical wall and a plurality of chambers connected to suction ducts are disposed in close proximity to the inner surface of the drum wall.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. ll illustrates diagrammatically one form of apparatus for coating separate labelswith adhesive and applying them to a continuous web of release paper, and

FIG. 2 is a diagrammatic elevation of a second form of apparatus for the same purpose.

DETAILED DESCRIPTION OF THE INVENTION In the embodiment illustrated in FIG. I, the-separate labels 10 which have been printed on flat sheets by any suitable process, e.g., letterpress or screen printing where the quality achieved is acceptable, or a high quality process such as offset lithography or gravure, are cut and trimmed to finish size by known means and stacked face down in a magazine: 11 from which they are fed in succession to a belt conveyor 12. The conveyor 12 carries the labels 10 past an applicator 14 which coats the upward-facing reverse sides of the labels with a pressure-sensitive adhesive composition which may be either water or solvent based.

The applicator M for the pressure-sensitive adhesive composition may, for example, comprise a roller, a-

doctor blade, means for spraying or screening the adhesive on to the labels, or means for measuring out and blowing the adhesive on to them.

From the applicator 14, the labels are transported by a second belt conveyor 15 through a heating device 16 which dries the adhesive coating, e.g., by causing hot air to circulate over the coating or by infra-red heating. Both the conveyors 12 and 15 may, if desired, be provided with gripping devices, e.g., mechanical or vacuum operated grippers, for holding the labels 10. The labels 10 are then fed by the conveyor 15 to a continuous travelling web 17 of backing paper which has a release coating, e.g., of a silicone composition. The web 17 is unwound from a reel 18 and wound upon a reel 19 after application of the labels 110.

A gate 20 is controlled by a photo-electric cell 21 which is sensitive to the presence of a preceding label on the web 17, so that when the web is free the gate 20 opens to admit the next label 10. Alternatively, instead of using the gate 20, gearing (not shown) may be provided to synchronize the speed of the web 17 with the speed of the conveyors l2, 15 which feed the labels to it. A pair of pressure rollers 22, 23 press the labels against the web 37 to attach them securely thereto. The web 17- with the labels l attached in closely spaced positions,-is then wound upon the reel 19.

In the embodiment of the invention illustrated'in FIG. 2, the separate labels, in the form of flat sheets cut to finished size, are placed face down in a stack 29 on a table 30 and located against a fixed wall 2%. The table 30 is freely suspended from chains or wire cables 31 passing over sprockets or pulleys 32 and wound upon a drum 33. An electromagnetic regulating unit 34 of known type is arranged to control the height of the table 38) so as to keep the top label in the stack 29 in contact with the underside of a reciprocable suction bar 35. The bar 35 is of known construction, incorporating a suction duct in its underside for gripping the top label. It is mounted on one end of an arm 36pivoted at 37 on the upper end of one arm of a bell-crank lever 38 which is itself pivoted at 39 on the frame 40 of the apparatus. The other end of the arm 36 carries a roller 41 engaging an adjustable inclined ramp 42. The other arm of the bell-crank lever 38 carries a roller 43 engaged by a cam 44 mounted on a shaft 45 which can be rotated by an electric motor (not shown).

Rotation of the shaft 45 and cam 44 causes oscillation of the bell-crank lever 38 and consequent back .and forward -reciprocating movement of the arm 36 and suction bar 35 on an arc centred on the pivot 39. At the same time, a link 46 connecting the shaft 45 with a ratchet device 461 on the drum 335 permits the table 30 to rise by the thickness of one label, under the overall control of the regulating unit 34. Engagement of the roller 41 with ramp 42 causes the arm 36 to tilt slightly as it moves forward (to the right in FIG. 2). Each time the bar 35 is thus moved forward it picks up the front (i.e., right-hand) part of the toplabel of the stack 29 and feeds it forward over the top of the wall 28. At the end of the stroke, the front edge of the label is engaged in the nip between a small roller 47 and a large diameter drum 48. Instead of using a front edge feed as described above, the sheets may be fed to the drum 48 by a back edge feeder of known type.

The drum 48 has a perforated cylindrical wall 49 and is mounted for rotation on a shaft t) journalled in the frame 4%. It is driven by a motor (not shown) in an anticlockwise direction as seen in FIG. 2.

On the inside of the perforated drum wall 49 are disposed stationary suction devices for gripping labels fed to the drum by the suction bar 35. These suction devices comprise firstly an inverted trough-shaped member 51 extending parallel to the drum shaft 50 and having its side walls 52 in sealing contact with the inner surface of the rotary drum wall 49, one on each side of the position of the small roller 47 on the outside of the drum. The interior of the trough 51 is connected through a suction duct 53 to a pump capable of reducing the pressure in the trough to a relatively low figure,

so that a label fed forward by the suction bar 35 to the nip between the roller 47 and drum 4% will be gripped by the suction applied through the trough 5 i and perforated drum wall 49 and thereafter carried forward by the drum.

, Beyond the trough 511 in the anti-clockwise direction of rotation of the drum 48, are arranged three suction chambers 54, 55, 56, each of which is connected to a pump through a respective suction duct 57, 58, 59, and applies suction through the perforated drum wall 49 to hold the labels carried forward by the drum. The pressure in the chambers 54, 55, 56 need not be reduced to as low a'figure as in the trough 51.

Beneath the drum 48, just beyond the roller 47, is an adhesive applicator 60 of known type, shown here as comprising a vessel 61 for containing the pressuresensitive adhesive composition in liquid form (e.g., in solution), a roller 62 dipping into the adhesive, a small regulating roller 63 in contact with the roller 62 to regulate the amount of adhesive withdrawn from the vessel 61 and an applicator roller 64 which transfers adhesive from the roller 62 to the backs of the labels carried forward by the drum 48.

Around the outside of the drum 48, extending over more than half its circumference opposite to the suction chambers 54, 55, 56, is disposed a drying tunnel 65 fed with hot air through ducts '66, 67, 68 for drying the adhesive applied to the labels by the applicator 60.

A pick-up roller 70 is disposed on the outside of the drum 48, beyond the end of the drying tunnel 65 and immediately opposite the end of the last suction cham ber 56, and is resiliently urged against the drum 48.

. This pick-up roller 70 is fed with a continuous web 71 of silicone-coated release paper, having its coated surface facing the drum 48, from a supply reel 72.

The labels which have been carried around the drum 48 are released therefrom as they reach the end of the suction chamber 56, and at this moment they contact and adhere to the web 7l. From the pick-up roller 70, the web 71 with the labels attached to it passes to a conventional reeling mechanism, illustrated here as comprising a roller 73 and reel 74 on which the web is reeled. 1

It is thus practicable to produce a reeled web of selfadhesive labels without the limitation of size or quality previously thought to be unavoidable.

I claim:

l. A process forthe production of a continuous reel of self-adhesive labels, wherein the labels are produced as separate flat sheets cut to finished size and stacked, the separate labels are then fed in succession from the stack onto the surface of a drum and held thereon by vacuum means while being fed to an applicator by which they are coated individually on their reverse sides with a pressure-sensitive adhesive composition, the adhesive is dried by passing the labels through a hot air chamber extending about a substantial part of the periphery of the drum and the labels are applied successively by their adhesive coated sides to a continuous web of release paper which moves against said drum and which is then reeled.

2. A process according to claim 1 wherein the application of the labels to the web of release paper is controlled by a photo-electric cell sensitive to the presence of a preceding label on the web.

3. A process according to claim 1 wherein after application of the labels, the web with the labels thereon is passed between a pair of pressure rollers to ensure the attachment of the labels.

4. Apparatus for producing continuous reels of selfadhesive labels, comprising means for supporting a stack of labels in the form of separate flat sheets cut to finished size, means for feeding separate out labels in succession from the stack to an applicator which is arranged to coat the reverse sides of the labels individually with a pressure-sensitive adhesive composition, a rotatable drum having internal suction means for receiving and holding the labels on its periphery with their reverse sides outwards, drying means extending,

around a substantial part of the periphery of the drum for drying the adhesive on the reverse sides of the labels, means for subsequently applying the labeis successively by their adhesive coated sides to a continuous web of release paper, and means for reeling the contin-.

uous web.

Apparatus according to claim twhercin the applicator comprises a roller.

6. Apparatus according to claim 4 wherein the applicator comprises a doctor blade.

'7. Apparatus according to claim 4 wherein the applicator comprises means for spraying the adhesive on to the labels.

close proximity to the inner surface of the drum wall. :I: i: k 

1. A process for the production of a continuous reel of selfadhesive labels, wherein the labels are produced as separate flat sheets cut to finished size and stacked, the separate labels are then fed in succession from the stack onto the surface of a drum and held thereon by vacuum means while being fed to an applicator by which they are coated individually on their reverse sides with a pressure-sensitive adhesive composition, the adhesive is dried by passing the labels through a hot air chamber extending about a substantial part of the periphery of the drum and the labels are applied successively by their adhesive coated sides to a continuous web of release paper which moves against said drum and which is then reeled.
 2. A process according to claim 1 wherein the application of the labels to the web of release paper is controlled by a photo-electric cell sensitive to the presence of a preceding label on the web.
 3. A process according to claim 1 wherein after application of the labels, the web with the labels thereon is passed between a pair of pressure rollers to ensure the attachment of the labels.
 4. Apparatus for producing continuous reels of self-adhesive labels, comprising means for supporting a stack of labels in the form of separate flat sheets cut to finished size, means for feeding separate cut labels in succession from the stack to an applicator which is arranged to coat the reverse sides of the labels individually with a pressure-sensitive adhesive composition, a rotatable drum having internal suction means for receiving and holding the labels on its periphery with their reverse sides outwards, drying means extending around a substantial part of the periphery of the drum for drying the adhesive on the reverse sides of the labels, means for subsequently applying the labels successively by their adhesive coated sides to a continuous web of release paper, and means for reeling the continuous web.
 5. Apparatus according to claim 4 wherein the applicator comprises a roller.
 6. Apparatus according to claim 4 wherein the applicator comprises a doctor blade.
 7. Apparatus according to claim 4 wherein the applicator comprises means for spraying the adhesive on to the labels.
 8. Apparatus according to claim 4 wherein the applicator comprises means for screening the adhesive on to the labels.
 9. Apparatus according to claim 4 wherein the means for feeding the cut labels from the stack to the applicatoR comprise a reciprocable suction bar.
 10. Apparatus according to claim 6 wherein the drying means comprises an enclosure and means for supplying hot air to the enclosure.
 11. Apparatus according to claim 6 wherein the drum has a perforated cylindrical wall and a plurality of chambers connected to suction ducts are disposed in close proximity to the inner surface of the drum wall. 